Abstract: A rotary switch, used to select the operating range of an automatic transmission, controls solenoid-operated valves corresponding to the selected range. The valves open and close a connection between a range valve and control pressure source. The range valve includes two spools having three positions. The spools are biased apart by a compression spring located between the spools. One valve position opens the fluid pressure source to a line that is pressurized to produce forward drive, a second position opens a connection between the fluid pressure source and a line that is pressurized to produce reverse drive, and a third position vents those lines to sump. The spring locates the spools at the third position. Control pressure force on opposite ends of each spool forces both spools to the first and second positions in response to the range selected by the vehicle operator.

Abstract: A control system (104)/method for a vehicular automated mechanical transmission is provided, which will compare input signals indicative of input shaft speed (IS) to the product of input signals indicative of output shaft speed multiplied by engaged gear ratio (OS*GR) to develop control parameters indicative of drivetrain torque magnitude and/or phase requiring a driveline torque transducer.

Abstract: In a speed change gear system (1) in accordance with the present invention for changing between forward movement and rearward movement of a vehicle and for changing a speed of the vehicle by selectively fixing sun gears, carriers and ring gears of a plurality of epicyclic gear devices with respective mating clutches (8, 14, 24, 28), a brake (29) is connected to an output shaft (21) of this speed change gear system (1) to share energy absorption of the respective clutches, and the hydraulic pressure for the brake (29) is controlled in accordance with a rotation rate of the output shaft (21). Therefore, these clutches (8,14,18,24,28) can be small-sized. When the brake (29) is released, a quantity of lubrication oil being supplied is reduced, and therefore the stirring resistance of the lubrication oil can be reduced, and the transmission efficiency can be satisfactory.

Abstract: A system and method for controlling the bypass clutch of an automatic transmission includes an electronic microprocessor, an electronic memory accessible to the microprocessor, solenoid-operated bypass valve, pressure actuated bypass clutche, a variable force solenoid-operated bypass valve, a torque converter bypass friction clutch, and control algorithms that produce output signals to control the state of the solenoid-operated valve. The vehicle speed at which the bypass clutch engages and disengages, according to a reference schedule, is compensated for loss of engine torque at conditions that differ from the conditions at which the reference schedule is defined. Vehicle speed is compensated for torque variation with reference to the ratio of current calculated engine torque divided by current engine output torque.

Abstract: In an automatic transmission according to the present invention, a coast brake cutoff valve is arranged between a range-pressure-producing manual valve and shift valves and, when changed over, selectively feeds oil to hydraulic engine brake servomotors. An engine brake solenoid valve is on/off controlled by a shifting output signal from a CPU, whereby the coast brake cutoff valve is selectively changed over. A lockout valve is arranged between the coast brake cutoff valve and the manual valve and is connected to one of shifting solenoid valves. The automatic transmission can therefore be operated without trouble even when an electrical problem occurs in the shifting solenoid valves and/or the engine brake solenoid valve.

Abstract: An automatic transmission control method and apparatus for a vehicle includes a first gear change mechanism in which an input shaft is connected to an output shaft of a fluid coupling and a rotational speed of the output shaft of the first gear change mechanism is changed by selectively controlling hydraulic oil supplied to and discharged from a plurality of first frictional engaging elements. It further includes a second gear change mechanism in which an input shaft is connected to the output shaft of the first gear change mechanism, the output shaft is connected to a driving wheel member and an output shaft rotational speed of the second gear change mechanism is controlled by selectively controlling the hydraulic oil supplied to and discharged from a plurality of second frictional engaging elements.

Abstract: An automatic transmission on an automobile has an input shaft, an output shaft, a plurality of power transmitting paths disposed between the input and output shafts for establishing respective gear positions, and a plurality of engaging elements for selecting one of the power transmitting paths at a time. A shift controller disengages a previous-position engaging element and engages a next-position engaging element to switch from one of the power transmitting paths to another for thereby effecting a shift from a previous gear position to a next gear position.

Abstract: A hydraulic control device for an automatic transmission including a first frictional engaging element for achieving a low-speed side position, a second frictional engaging element for achieving a position higher in speed than the low-speed side position, a third frictional engaging element for achieving a position even higher in speed than the high-speed side position, a regulator valve for regulating pressure from an oil pump to a predetermined pressure and reducing the predetermined pressure in response to supply of a pilot pressure, and a control valve for controlling the pressure from the regulator valve to a desired hydraulic pressure, for controlling hydraulic pressures to the plural frictional engaging elements.

Abstract: An automotive automatic transmission has a hydraulically operated clutch device and an electronic control unit. The clutch device includes drive and driven clutch plates and a piston for pressing the drive and driven clutch plates to establish an engagement therebetween when an oil chamber for the piston is fed with a certain amount of fluid. In order to control the clutch device, the following steps are employed, which are (a) issuing a first instruction signal to the clutch device; (b) feeding the oil chamber with the fluid by an amount which is sufficient for moving the piston from a rest position to a critical position which is ready for effecting the actual pressure against the drive and driven clutch plates; (c) issuing a second instruction signal to the clutch device; and (d) increasing the hydraulic pressure in the oil chamber to cause the piston to instantly establish the engagement between the drive and driven clutch plates.

Abstract: In a control system for an automatic transmission, when successive order signals are emitted so that shift changes are accomplished over multiple shift stages, a shift change ordered by an initial order signal is carried out before a shift change ordered by a last order signal is carried out if a shift gear mechanism has already started its operation. However, a shift change ordered by a last order signal is carried out, without shift changes ordered by an initial order signal and intermediate order signals being carried out, if the shift gear mechanism has not started its operation.

Abstract: A shift control arrangement for an automotive automatic transmission includes a control unit active to change the state of a solenoid disposed in a hydraulic circuit of an automatic transmission during shifting so as to appropriately effect engagement and/or release of a frictional element of the automatic transmission. The control unit is further provided with a fluid temperature compensating portion so as to delay or advance a time of actuation of the solenoid, according to a detected gear ratio, to compensate for changes in fluid viscosity due to temperature, such that optimal shift characteristics for the frictional element are always maintained.

Abstract: An automatic transmission control system couples frictional coupling element, such as a low reverse brake, so that the frictional coupling element provides different torque transmissive capacities in a reverse gear and a first gear in which engine braking is available. The system includes a pressure regulator which regulates a coupling pressure, by which the frictional coupling element is coupled and which is controlled and gradually supplied to the frictional coupling element, during a shifting of the automatic transmission to a reverse gear. The pressure regulator is disabled from regulating the coupling pressure in the reverse gear.

Abstract: A control system for controlling an automotive automatic transmission which comprises a friction element operated by a hydraulic pressure. The control system comprises a first device for judging whether a gear change of the transmission is necessary or not in accordance with the running condition of the vehicle; a second device for lowering the hydraulic pressure when the first device judges a necessity of the gear change; a third device for increasing the hydraulic pressure when a difference between the maximum engine speed appearing after starting of gear change operation and a current engine speed is greater than a predetermined degree; and a fourth device for increasing the hydraulic pressure when a predetermined time passes from the time when the first device has judged the necessity of the gear change irrespective of operation of the third device.

Abstract: In a control system for an automotive automatic transmission having a friction element powered by a line pressure, a gear ratio provided by the transmission is measured. An inertial phase keeping time is measured, which is the time for which the transmission assumes an inertial phase. A line pressure adjuster is employed to adjust the line pressure in a manner to harmonize the inertial phase keeping time with a predetermined time. An inertial phase starting time is measured, which is the time elapsed until the inertial phase of the transmission starts. A line pressure increasing device is employed for increasing the line pressure irrespective of condition of the line pressure adjuster when the inertial phase starting time exceeds a first given time. An inhibitor is employed to suppress the operation of the line pressure increasing device in case wherein even when the inertial phase starting time exceeds a second given time longer than the first predetermined time, the change of the gear ratio does not occur.

Abstract: A hydraulic control has valves for controlling the drive range selection and ratio interchange in a power transmission including a selector valve, a shift valve and a coast control valve. Each of these valves has a rotary spool distribution member for directing pressurized fluid to passages in a housing from which the fluid is delivered to the proper transmission mechanisms. The control simultaneously exhausts other transmission mechanisms.

Abstract: A shift control system in an automatic transmission controls a shifting which necessitates redeployment of friction elements so that one friction element is engaged while the other friction element is released. In reply to a shift command, the shift control system starts to control one of the engagement pressure of the friction element to be engaged or the disengagement pressure of the friction element to be disengaged. Next, the shift control system starts to control the other one of the engagement pressure or the disengagement pressure at a moment at which a preset time has elapsed from the start of the shift command. The preset time is corrected so as to decrease a physical quantity indicative of discord of the timing between the engagement and the disengagement. Accordingly, the preset time firmly takes a proper time so as to carry out the deployment of both friction elements at a synchronized point due to such a learning control. This enables the shift feeling to always be kept good.

Abstract: An R-N-D control valve of a hydraulic control system is disclosed which ensures the prevention of shock that may occur at the time of an "N-R" and an "N-D" manual shift, by unifying a shift control pressure with one valve in the case of an "N-R" shift and an "N-D" shift and first-second speed shift. The present invention discloses that a line pressure generated from a manual valve is changed to a control pressure controlled by the proportional control of a linear valve, and transmitted to each clutch and brake according to the movement position of a spool of a valve by the line pressure.

Abstract: (1) Various gear states are selected by movement of a shift lever 2 in a longitudinal shift path 13 and the gear stage is automatically shifted from starting to the maximum gear stage in an automatic speed change position D, so that an operator can run a vehicle with increased safety and easy operation without operation of the shift lever 2. (2) When a push button switch 3 provided in the shift lever 1 is pressed during the automatic speed change running, the gear stage during the running is fixed, so that inadvertent automatic shift is prevented and an optimum speed stage is maintained when the work load on the vehicle's engine changes, for example when the vehicle encounters a slope or a change in load during in operation. (3) When the gear stage is fixed in the automatic speed change position D and the shift lever 2 is transversely moved in the transverse shift path 14, the operator can vary the stages while varying one stage a time with the operator's will.

Abstract: A method and apparatus for increased clutch capacity in an automatic vehicle transmission having a nested clutch pair. An electronic control unit controls a pulse width modulator which applies control signals to the actuating solenoid valves of the nested pair of clutches. The electronic control unit operates to reduce the pressure on an engaged clutch of the pair during the period of time that the other clutch is being actuated during the shift. Once the shift is completed, the operating pressure on the previously engaged clutch is restored to a normal operating pressure. Provisions are also made for assuring that the period of time required for the shift is maintained between threshold limits or within a window of time. This adaptive feature precludes excessively short or long shifts.

Abstract: A process is described for controlling the actuating pressure in a control element (shift element) of an electrohydraulically controlled transmission of a motor vehicle during a change of the gear position. In the case of downshifts in the coasting operation, the hydraulic pressure in the transmission is preferably increased with the initiating of the shifting by way of the pressure control valve in a time-limited manner. Starting from a presettable or preset basic value, the amount of this filling pulse is automatically and in steps for each control operation in the course of the operation of the transmission adapted to a target value in such a manner that an input rotational speed of the transmission or a rotational speed of a driving engine connected in front of the transmission follows a predetermined sequence of movements.

Abstract: A transmission range selection apparatus including electrically activated range selection valving elements for selectively defining fluid supply states for each primary operating mode of the transmission. Two electrically operated valving elements selectively define fluid supply states for each of four operating modes: Park/Neutral, Reverse, Drive and Drive/Braking. These four operating modes, in conjunction with electronic positioning of the transmission shift valves enables automatic selection of any operating mode of the transmission by a state-of-the-art electronic control unit.

Abstract: The invention comprises mechanism for reducing hydraulic pressure on the engaged forward or reverse clutch when the decelerator pedal is fully depressed. The mechanism comprises an electric switch that is coupled to the decelerator pedal linkage for energizing a solenoid valve. The solenoid valve couples the modulation accumulator of the power shift tranmission to sump when the electric switch is closed. This decreases the hydraulic pressure on the engaged forward or reverse clutch so that it can slip if braking force is applied to the vehicle.

Abstract: A valve assembly in a fluid system of a vehicle transmission directs fluid flow from a fluid source to at least one fluid actuated device. The assembly includes a first solenoid-actuated valve for directing fluid flow to a first fluid actuated device and a second solenoid-actuated valve for directing fluid flow to the first fluid actuated device. A manually actuated manual valve in the transmission is moveable for directing fluid flow from a fluid source to either the first or second solenoid-actuated valves in the hydraulic circuit, when the manual valve is actuated, which permits the vehicle to operate in various gears or operating modes as desired.